Phenylalanine is an amino acid, a "building block" of protein. There are three forms of phenylalanine: D-phenylalanine, L-phenylalanine, and the mix made in the laboratory called DL-phenylalanine.
D-phenylalanine is not an essential amino acid. Its role in the body is not currently understood. L-phenylalanine is an essential amino acid. It is the only form of phenylalanine found in proteins. Major dietary sources of L-phenylalanine include meat, fish, eggs, cheese, and milk.
Phenylalanine is most commonly used for a skin disorder that causes white patches to develop on the skin (vitiligo). It is also used for aging skin, pain, obesity, and many other conditions, but there is no good scientific evidence to support these uses.
The body uses phenylalanine to make chemical messengers, but it is not clear how phenylalanine might work.
When taken by mouth: L-phenylalanine is LIKELY SAFE for most people when taken in amounts commonly found in foods. L-phenylalanine is POSSIBLY SAFE when taken as medicine, short-term. D-phenylalanine is POSSIBLY SAFE when used as a single dose of up to 10 grams. There isn't enough reliable information to know if D-phenylalanine is safe when used as more than a single dose.
When applied to the skin: L-phenylalanine is POSSIBLY SAFE when applied as a cream, short-term.
Special Precautions & Warnings:Pregnancy and breast-feeding: L-phenylalanine is LIKELY SAFE when consumed in amounts commonly found in foods by pregnant patients who have normal phenylalanine levels. But having too much phenylalanine during pregnancy can increase the chances of birth defects. For patients who process phenylalanine normally and have normal levels, it is probably fine to get the amount of phenylalanine found in food, but supplements should be avoided. For pregnant patients who have high levels of phenylalanine, such as those with a condition called phenylketonuria (PKU), even normal food amounts are UNSAFE. For these patients, experts recommend a low phenylalanine diet for at least 20 weeks before getting pregnant. This should reduce the risk of birth defects.
While breast-feeding, Phenylalanine it is LIKELY SAFE for breast-feeding mothers whose bodies' process phenylalanine normally to consume the amount of L-phenylalanine found in food. However, do not take more.But there isn't enough reliable information to know ifNot enough is known about the safety of taking L-phenylalanine is safe to use in medicinallarger amounts duringwhen breast-feeding.
There isn't enough reliable information to know if D-phenylalanine is safe to use when pregnant or breastfeeding. Stay on the safe side and avoid use.
Phenylketonuria (PKU) and other conditions that cause high levels of phenylalanine: Phenylalanine should be avoided in people with certain inherited disorders that cause their bodies to build up too much phenylalanine. Phenylketonuria (PKU) is one of these diseases. People with this disorder can develop mental retardation, high blood pressure, stroke, and many other serious health issues if they consume phenylalanine. PKU is so serious that babies are screened at birth to determine whether they have the disorder and will need a special diet to avoid these problems.
Schizophrenia: Use with caution. Phenylalanine can make a movement disorder (tardive dyskinesia) in people with schizophrenia worse.
Interaction Rating=Major Do not take this combination.
Levodopa is used for Parkinson's disease. Taking phenylalanine along with levodopa can make Parkinson's disease worse. Do not take phenylalanine if you are taking levodopa.
Medications for depression (MAOIs)
Interaction Rating=Moderate Be cautious with this combination.
Phenylalanine can increase a chemical in the body called tyramine. Large amounts of tyramine can cause high blood pressure. But the body naturally breaks down tyramine to get rid of it. This usually prevents the tyramine from causing high blood pressure. Some medications used for depression stop the body from breaking down tyramine. This can cause there to be too much tyramine and lead to dangerously high blood pressure.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.
Medications for mental conditions (Antipsychotic drugs)
Interaction Rating=Moderate Be cautious with this combination.
Some medications for mental conditions might cause jerky muscle movements. Taking phenylalanine along with some medications for mental conditions might increase the risk of jerky muscle movements.
Some medications for mental conditions include chlorpromazine (Thorazine), clozapine (Clozaril), fluphenazine (Prolixin), haloperidol (Haldol), olanzapine (Zyprexa), perphenazine (Trilafon), prochlorperazine (Compazine), quetiapine (Seroquel), risperidone (Risperdal), thioridazine (Mellaril), thiothixene (Navane), and others.
There are no known interactions with herbs and supplements.
There are no known interactions with foods.
The following doses have been studied in scientific research:
- A skin disorder that causes white patches to develop on the skin (vitiligo): 50-100 mg/kg of L-phenylalanine once per day has been used. L-phenylalanine 50 mg/kg three times per week for up to 3 months has also been used.
- A skin disorder that causes white patches to develop on the skin (vitiligo): Applying a 10% phenylalanine cream to the skin has been used.
- A skin disorder that causes white patches to develop on the skin (vitiligo): Phenylalanine 100 mg/kg twice weekly for 3-4 months has been used.
2-amino-3-phenyl-propanoic acid, Acide Alpha-aminohydrocinnamique, Acide Isovalérique de Phénylalanine, Alpha-aminohydrocinnamic Acid, Beta-phenyl-alanine, Bêta-phenyl-alanine, DLPA, D-Phenylalanine, D-Phénylalanine, DL-Phenylalanine, DL-Phénylalanine, D,L-Phenylalanine, D,L-Phénylalanine, Fenilalanina, L-Phenylalanine, L-Phénylalanine, Phenylalanine Ethyl Ester HCl, Phenylalanine Isovaleric Acid, Phenylalanine Methyl Ester HCl.
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